Japanese Patent Application No. 2001-131809, filed on Apr. 27, 2001, is hereby incorporated by reference in its entirety.
The present invention relates to a clutch-brake system and a press machine using the same.
For example, a press machine 1P shown in FIG. 2 is formed by a frame 10P on which a drive shaft 20P and flywheel 25P are rotatably mounted but not movable in an axis (Z) direction (or longitudinal direction) of the drive shaft 20P. Reference numeral 26P denotes a cover which houses a clutch device integrally fixed to the flywheel 25P.
A clutch device 30P constructed according to the prior art includes a clutch disc 41P, a clutch friction plate 31P, an air intake port 48P and a spring 46P. The clutch device 30P is mounted on the drive shaft 20P at one end (right as viewed in FIG. 2) for driving a slider (not shown).
The clutch disc 41P includes: an inner stationary disc 41IP mounted on the flywheel 25P to be synchronously rotatable and not to be movable in the Z direction, when the flywheel is rotatably supported on the drive shaft 20P through a bearing 14P; and an outer movable disc 41OP mounted on the flywheel 25P to be synchronously rotatable and to be movable in the axial (Z) direction along a guide pin 45P.
The clutch friction plate 31P is mounted on the drive shaft 20P at one end (right end) to be synchronously rotatable with the drive shaft 20P and to be movable through a spline structure 32 or the like in the Z direction. More particularly, the clutch friction plate 31P has a rotatable holding portion 31R mounted on the drive shaft 20P through an anchoring device 15P for synchronized rotation and an anchor portion 31K for screwedly anchoring the clutch friction plate 31P, these portions being movable relative to each other through the spline structure 32 or the like in the Z direction. Structures of hydraulic lubrication and alignment control incorporated into the spline structure 32 or the like are omitted from FIG. 2.
The outer disc 41OP is biased rightward as viewed in FIG. 2 by the spring 46P mounted around a guide pin 45P in the normal (or clutch release) state, in which state the outer disc 41OP is in its clutch release (OFF) state and spaced apart from the clutch friction plate 31P. Reference numeral 43P denotes linings.
When air is supplied from a rotary joint 49P into a cylinder chamber 26SP through the air intake port 48P, a piston 41DOP is moved leftward as viewed in FIG. 2 against the bias of the spring 46P. Thus, the outer movable disc 41OP integrally mounted on the piston 41DOP is moved leftward to urge the clutch friction plate 31P against the inner stationary disc 41IP while moving the same toward the inner disc 41IP. As a result, the clutch device will be switched to the clutch engagement (ON) state.
More particularly, the clutch device 30P can selectively be switched to either of the clutch engagement state that can transmit the rotational energy of the flywheel 25P (26P) to the drive shaft 20P or the clutch release state that cannot transmit the rotational energy to the drive shaft 20P, in response to the air supply or exhaust as in FIG. 2.
A brake device 50P constructed according to the prior art includes a brake disc 61P, a brake friction plate 51P, an air intake port 68P and a spring 66P and is mounted on the drive shaft 20P at the other end (leftward end as viewed in FIG. 2).
The brake disc 61P includes an inner stationary disc 61IP mounted on a frame 10P (or bracket 19P) not to be movable in the Z direction and an outer movable disc 61OP mounted on the frame 10P (or bracket 19P) to be movable in the axis direction along a guide pin 67. Reference numeral 63P denotes linings.
The brake friction plate 51P is mounted on the drive shaft 20P at the other (leftward) end to be synchronously rotatable with the drive shaft 20P and to be movable through the spline structure or the like in the Z direction. More particularly, the brake friction plate 51P includes a rotatable rotation holding portion 51R and an anchoring portion 51K for screwedly securing the brake friction plate 51P, these portions being movable relative to each other through the spline structure 52 or the like in the Z direction.
The alignment in the rotation holding portion 51R of the brake friction plate 51P can be controlled by using the outer peripheries of a control ring member 18 and lid member 19F. An O-ring 53 is provided to seal for lubricant. In other words, the brake device 50P has the lubricating structure (53 and so on) and the alignment control structure (18, 19F and so on) associated with the spline structure 52 or the like.
When the compressed air within the cylinder chamber 61SP is exhausted through the air intake port 68P in the brake release state, the outer movable disc 61OP is moved rightward as viewed in FIG. 2 under the bias of the spring 66P mounted around a guide pin 65P to urge the brake friction plate 51P against the inner stationary disc 61IP while moving the same toward the inner disc 61IP. Thus, the brake device 50P can be switched to its brake engagement (ON) state.
On the contrary, if air is supplied into the cylinder chamber 61SP through the air intake port 68P, a piston 61PP in the interior of the cylinder chamber 61SP is moved leftward as viewed in FIG. 2 against the bias of the spring 66P to push a bolt member 62 fastened on the outer disc 61OP. Thus, the outer disc 61OP is moved leftward to separate it from the brake friction plate 51P. This state is the brake release (OFF) state.
In other words, the brake device 50P can selectively be switched to either of the brake release state that releases the braking force to permit the rotation in the drive shaft 20P or the brake engagement state that can apply the braking force to the rotating drive shaft 20P, in response to the air supply or exhaust as in FIG. 2.
A clutch-brake system is provided by combining the clutch device 30P with the brake device 50P. The clutch-brake system can be switched to the clutch engagement and brake release state in response to the air supply and to the clutch release and brake engagement state in response to the air exhaust.
A press machine including such a clutch-brake system has been required to more improve in speed and accuracy, as in the other industrial machines and so on. In the viewpoint of versatility, differentiation and so on, it is strongly required that the press machine is improved in response on start or stop or both start and stop.
However, the prior art clutch device 30P is designed to provide the braking force by urging the movable clutch disc 41OP against the stationary clutch disc 41IP while moving the clutch friction plate 31P on the drive shaft 20P in the axial direction. Therefore, the clutch device 30P is of complicated, large-sized and weighted structure, leading to increase of the manufacturing cost. The clutch disc 41OP and clutch friction plate 31P will easily be degraded in rapid and smooth movement. Since the clutch device 30P has an increased inertial mass, it is difficult that the clutch device 30P shows quick response. Furthermore, the mechanical backlash and play will reduce the accuracy, provide a source of noise and shorten the mechanical life. This is true of the brake device 50P.
And yet, the clutch and brake devices 30P, 50P have many mechanical setting locations since they are of complicated structure and require mechanical delicate adjustments. Thus, a disagreement may easily be created between the responsibilities of the clutch and brake devices 30P, 50P.
If the starting point of a pressing process is to be strictly managed, the degradation of the clutch action in the clutch device 30P will also degrade the accuracy in product. To improve the accurate work in the press machine, the clutch action must be more improved in speed.
On the other hand, if the brake operation speed of the brake device 50P is low when the pressing process is suspended, the quality of the products would be affected. In order to further improve the yield of the products, the brake operation speed has to be further increased.
If the ability of the clutch device is improved, the braking characteristics (response and speed) of the brake device may be less associated with the clutch device, or vice versa. To product various high-precision parts such as electronic parts with increased accuracy, however, it is increasingly required that any disagreement between the clutch and brake characteristics (response and speed) is eliminated, thereby appropriately combining these characteristics to improve the whole performance in the clutch-brake system.
The present invention may provide a clutch-brake system and a press machine using the same, which can greatly improve the clutch and/or brake characteristics.
According to one aspect of the present invention, there is provided a clutch-brake system comprising: a flywheel; a drive shaft driven by rotational energy transmitted from the flywheel; a clutch device selectively switchable between an operation state in which the rotational energy from the flywheel is transmitted to the drive shaft, and a non-operation state in which no rotational energy is transmitted to the drive shaft; and a brake device selectively switchable between an operation state in which a braking force is applied to the drive shaft during rotation, and a non-operation state in which the braking force is released to permit rotation of the drive shaft,
wherein at least one of the clutch and brake devices has: a friction plate mounted on the drive shaft to be synchronously rotatable on the drive shaft, but not to be movable in an axis direction of the drive shaft; and first and second discs provided on the opposite sides of the friction plate in the axis direction of the drive shaft, and movable in the axis direction, and
wherein at least one of the clutch and brake devices synchronously moves the first and second discs in the opposite directions along an axis of the drive shaft, enabling to selectively switch between the operation state and the non-operation state.
If this configuration is applied to a clutch device, the clutch device may include: a clutch friction plate mounted on the drive shaft to be synchronously rotatable on the drive shaft, but not to be movable in the axis direction of the drive shaft; and first and second clutch discs provided on the opposite sides of the clutch friction plate in the axis direction of the drive shaft, and movable in the axis direction.
In the clutch device, the first and second clutch discs are normally separated from each other and selectively switched into a clutch release state in which the first and second clutch discs are separated from clutch friction plate, under the bias of a spring, for example. At this time, the clutch friction plate is stationary fixed to the drive shaft.
If the clutch device is actuated to switch to the clutch engagement state, the first and second discs are synchronously moved toward each other along the axis of the drive shaft (that is, the first clutch disc is moved from left to right while the second clutch disc is moved from right to left, for example)m to sandwich the clutch friction plate, under the action of a piston.
Thus, the clutch device can selectively be switched from the clutch release state to the clutch engagement state. At this time, the amount of transfer (or stroke) in each of the first and second clutch discs may require only one-half prior-art stroke, thereby reducing the operation time by half.
Therefore, the clutch operational characteristics (response and speed) can highly be improved. Since the clutch friction plate is fixedly mounted on the drive shaft, any spline structure or the like, which would be required in the prior art, may be eliminated to reduce the inertial mass, thereby effectively improving the quick response.
The clutch friction plate may be fixed to an end surface of the drive shaft. In comparison with the prior art requiring the spline structure, hydraulic lubricating structure and alignment control structure, all for moving the clutch friction plate along the axis, the clutch device of the present invention may greatly be simplified in structure and reduced in cost. Moreover, the mechanical backlash and play between components may be reduced to decrease the noise level. In addition, the mechanical life may be increased. Since the clutch operation can more early be provided, the clutch device may appropriately be synchronized in operation with the brake device (or brake release operation), thereby reducing the disagreement of operation between the clutch and brake devices.
If the aforementioned configuration is applied to the brake device, the later may include: a brake friction plate mounted on the drive shaft to be synchronously rotatable on the drive shaft, but not to be movable in the axis direction of the drive shaft; and first and second brake discs provided on the opposite sides of the brake friction plate in the axis direction of the drive shaft, and movable in the axis direction.
In the brake device, the first and second brake discs are normally moved toward each other along the axis of the drive shaft under the bias of a spring, and can be selectively switched to the brake engagement state wherein they engage the brake friction plate, for example. At this time, the brake friction plate is stationary fixed to the drive shaft.
When the brake device is switched to its brake release state, the first and second brake discs are synchronously moved away from each other or outwardly from the brake friction plate along the axis (e.g., the first brake disc is moved from left to right while the second brake disc is moved from right to left) and placed in no-contact with the brake friction plate, against the bias of the spring, in response to the supply of compressed air, for example.
Thus, the brake device can selectively be switched from the brake engagement state to the brake release state. At this time, the amount of transfer in each of the first and second brake discs may require only one-half prior art stroke, thereby reducing the operation time by half.
Therefore, the brake operational characteristics (response and speed) can highly be improved. Since the brake friction plate is fixedly mounted on the driveshaft, furthermore, any spline structure or the like, which would be required in the prior art, may be eliminated to reduce the inertial mass, thereby effectively improving the quick response.
The brake friction plate may be fixed to the drive shaft, or an end surface of the drive shaft, for example. In comparison with the prior art requiring the spline structure, hydraulic lubricating structure and alignment control structure all for axially moving the brake friction plate, the brake device of the present invention may greatly be simplified in structure and reduced in cost. Moreover, the mechanical backlash and play between components may be reduced to decrease the noise level. In addition, the mechanical life may be increased. Since the brake operation can more early be provided, the brake device may appropriately be synchronized in operation with the clutch device (or clutch release operation), thereby reducing the disagreement of operation between the clutch and brake devices.
The aforementioned configuration may be applied to both the clutch and brake devices.
In this case, the above effects can be implemented in each of the clutch and brake devices, and the inertial mass on the side of the drive shaft can be further decreased, so that the clutch operation characteristics (response and speed) and the brake operation characteristics (response and speed) can be greatly improved.
The clutch friction plate may be fixed to one end surface of the drive shaft, and the brake friction plate may be fixed to the other end surface of the drive shaft. Thus, any spline structure for moving these friction plates along the axis can be perfectly eliminated to simplify the clutch and brake devices in structure and to reduce them in cost. And yet, the mechanical life can highly be increased and the noise may more be reduced. In addition, the clutch operation and brake release, or the clutch release and brake operation may surely and reliably be carried out at the same time.